A software-defined data center is an architectural approach to information technology (IT) infrastructure that extends virtualization concepts to all of the data center's resources and services. In a software-defined data center, services such as networking, compute, and storage are pooled, aggregated, and managed by an intelligent, policy-driven software controller.
A proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client may connect to a proxy server and request a service from a different server. The proxy server may evaluate the request as a way to simplify and control access to data and resources.